Cryogenic Refurb Kit for Alcon Solenoid (P/N 13390992)

For cryogenic solenoid valves, Chart moved from Alcon to SMC in October 2007. In order to repair the existing valve, customers can now order a replacement SMC solenoid valve or an Alcon solenoid valve refurb kit. The new SMC valve lists at $185.00 whereas the refurb kit lists at $95.00. The plunger, plunger housing, springs, seals, and coil consists the refurb kit. The customers can fix their existing cryogenic valve without going through the hassle of disassembling the plumbing assembly with this kit.

Liquid Nitrogen Dewar Repair and Decontamination

When shipping a cryogenic dewar to MVE Chart for repair, the things to remember are:

 

1. All canisters should be taken out

2. Cork and cover must also be taken out

3. As explained by the method below, decontaminate the unit:

 

Chart Aluminum and MVE Dewars Procedure for Sanitizing and Decontaminating

 

The inner of the MVE aluminum cryogenic dewar is constructed with an aluminum that uses a fiberglass neck support. These stainless units are built completely from sheets of stainless steel. The use of any cleaning solution that does not react with aluminum or stainless is used for the sanitation method of these liquid nitrogen dewars, and in most cases a household detergent or mild soap solution is ideal. The cleaners and disinfectants that can be safely engaged in this are bleach, detergents, and mild soaps, hydrogen peroxide, chlorine/water and denatured alcohol.

 

Note: Any petroleum based cleaning solution should never be used. A solution by the name of EXPOR is utilized by U.S. Custom Service for incoming shipments from overseas consist of 9 parts water mixed with sodium chloride & lactic acid.

 

It is very important that the liquid nitrogen dewar’s inner vessel is completely cleaned with water and all cleaner remains are removed. Spraying the solution into the inner vessel is the best but agitation of the solution inside the inner is also tolerable. In the case of cryogenic vapor shippers and Double units, the cleaning mixture must be filled to its full capacity of the inner and then rinse. The cryogenic unit must be dried thoroughly before putting into service. We recommend setting vapor shipper Dewars upturned to drain and dry, but on the other hand, older vapor shipper models made before 1994 are not meant for this process. For cryogenic decontamination using 10% chlorine bleach with 90% water solution is still the best method. But, the agricultural professors at the University of Minnesota and Texas A & M have come to the conclusion that an enlarged mixture of chlorine bleach to 30% and 70% water taking into consideration some of the bovine and swine virus strains we see today and this solution will eradicate all known viruses except BSE.

 

In this disinfecting method, for 30 minutes swathe all inner surfaces of the liquid nitrogen dewar with the solution and then remove. With clean water rinse the decontaminated surfaces and after which remove the rinse water. Before putting into use allow the liquid nitrogen dewar to dry. This means invert the cryogenic vapor shippers and Doble unit Dewars by placing it on end to allowing drying. Note: Vapor shipper Dewars may take longer to renew to 100% capacity, though they are immediately ready after rinsing.

 

Cryogenic Discharge Device Transfer Hose

Now, MVE Chart sells a transfer hose which can be fitted to a liquid nitrogen freezer’s discharge device. This stainless steel transfer which comes standard with a phase separator hose, is two feet long and ¼ inch in diameter. The following part numbers should be referred for ordering purposes:

 

Phase Separator Size ..................................Part Number

Small ..............................................................14044143

Medium ..........................................................14044151

Cryogenic Fire Codes and Liquid Nitrogen Freezers

National Fire Protection Association has not put forth any codes that requires liquid nitrogen freezers or non-pressurized liquid nitrogen dewars to be secured to a wall. Each state or locality can pass more stringent codes, as long as the codes are not less relaxed than the established NFPA codes. Be sure to confirm with your local codes/ordinances to find if there are any variations from federal regulations. A good source of valuable information can come from your local fire inspector but remember the following while working with an inspector:

 

• Make sure the inspector refers to exact ordinance code violations when the citations are issued.
• Do not be afraid to question violations while working with the inspector
• You are eligible for a grace period to fix potential violations before any fines are assessed.

Cryogenic Freezer Operation Manuals

For each liquid nitrogen freezer, the MVE Chart does not hold precise user manuals; On the other hand, TEC 2000 and TEC 3000 manuals as well as the TEC 3000 Quick Start Guide, are very much available at www.chartbiomed.com. You can browse through the Resource Library to find resources on TEC2000/3000. This will bring you to associated literature where you can select the ones you may be interested on looking at.

To Disable a Temperature Probe on the TEC 2000

1. The cryogenic temperature probe which you would like to disable needs to be removed.
   
2. To cycle the power simply unplugging the cryogenic controller’s power source and plugging it back into the controller and remember to disconnect if your liquid nitrogen freezer is equipped with battery backup.
   
3. “DIAG ERROR SENS A” will be displayed on the cryogenic controller and will show “DISABLE ALARM? YES OR NO” 
   
4. Opting for “YES” is equal to disabling the port.
   
5. If desired, repeat this procedure for port B.
   

Broken Cryogenic Locking Tabs on Liquid Nitrogen Dewars

On some MVE Dewars comes a welded locking tab. In case the locking tab is broken beyond its utility, then the cryogenic locking tab must be re-welded back onto the liquid nitrogen dewar. The liquid nitrogen dewar needs to be returned to Chart’s facility in New Prague, Minnesota. Take up this alternative only if necessary because welding the locking tab onto the cryogenic Dewar gives grounds for risk to the integrity of the vacuum.

New Blog Format - MVE Chart Tech Tips

Thus far, our (Princton CryoTech's) blog has been a fairly random assortment of technical articles and snippets of information. 

As of tomorrow, December 16, 2008, we will begin to post technical articles on cryogenics from the resource center from MVE Chart.

These articles contain a range of information about MVE Chart cryogenic products. We will present them starting with the newest information first, and working our way down the list, as so it is easily found in our archives. 

Please dont hesitate to email us for specific information that you dont find here.

Freezer Racks Question and Answer

Q: Will the evaporation rate decrease if 6 more freezer racks are added?

A: No. Adding more freezer racks increases the heat transfer paths to LN2 as well as the evaporation rate. This is apparent when aluminum vertical freezer racks are being used since aluminum has a greater thermal conductivity than stainless steel. The result of evaporation rate is minimal when stainless freezer racks are being used. There is an added benefit to using aluminum freezer racks though; because of a slightly higher evaporation rate, the cryogenic freezer is filling slightly more frequently, essentially ‘charging’ the liquid nitrogen vapor with a fresh, cooler supply, meaning that the vapor temperatures inside your vapor phase freezer will be slightly cooler when using aluminum freezer racks.

Question and Answer - Cryogenic Freezers and Controllers

Q: I am informed that Japan operates on a 100V supply with their West Coast on 60Hz and their East Coast on 50Hz.  I tried to adjust the LN2 temperature for both cryogenic freezer probes A & B and in both cases it displayed (LN2 aborted). Next I went into the maintenance menu and discovered that LN2 was –273.1C. I rebooted the controller and found the same LN2 temperature.  Please explain how this reading occurred and how to correct the problem?

A: As per our reference material, it indicates that Japanese standard is 100-110VAC, 50-60Hz. The power supply used for Japan on the unit in question and in US for domestic applications is the same. It is made to function with US domestic standard nominal of 120VAC 60Hz. The tolerance on US domestic power is +/- 10% and on the low side it would be ~108VAC. The frequency would not be an issue because the power supply uses an unregulated step down transformer further negation of frequency issue, taking power supply to consideration, the controller rectifies it to DC internally and output is AC. From their outlets, if they are really getting only 100VAC then the output from the power supply to the control would be -20VAC. This would be trivial to properly operate the controller, so this should not cause the issue that is mentioned here.  If low voltage had been the issue, the controller would just shut off to a certain threshold voltage, which should be around the 20-21VAC point from the power supply to the control.

To correct this issue, you can replace the existing power supply with the new power supply which is currently use on the MDD units. It will provide the required output voltage with any input voltage from 100 to 250VAC and 50-60Hz since it built-in detector and switching device and is designed to accommodate +/-10%.  The MDD power supply should operate with an input as low as 90VAC or as high as 275VAC. It has been subjected to these extremes by TUV to be eligible for use in the MDD units. If you decide to install this power supply to sort out this issue, then P/N’s required to make the swap are as follows:

11795030 POWER SUPPLY 30VDC 1.2A 1 EA.

11859030 BRACKET POWER SUPPLY JEROME CE 1 EA.

11859021 BRACKET ADAPTOR FOR JEROME PS 1 EA.

2912191 PHPNHMS 4 EA.

Design Change for SC/3, SC8/5 and SC11/7

Design Change:

The new cork and cover design has been changed for SC/3, SC8/5 and SC11/7. A hinged base and cover has replaced slotted aluminum cover and the cork/cover is separated from the hinged lid. This shares the same cover assembly as Millennium and Doble units. The new part numbers are (Flat cork/cover 11209791), (Lid cover 5618176), (Hinge pin 5618156), (Hinged neck ring 5618166), (Cork/cover 11853674) (Notched lid for SC3/3 only 11838861) . This change has been in effect from January 2004. The old style replacement cork/covers are available till the unit stock supplies last and it may last through the reminder of 2004 but after which the cork/cover need to be replaced with the hinged lid.